Electrophysiology catheters are commonly-used for mapping electrical activity in the heart and/or for delivering energy to perform a therapeutic procedure. Various electrode designs are known for different purposes. In particular, catheters having basket-shaped electrode arrays are known and described, for example, in U.S. Pat. Nos. 5,772,590, 6,748,255 and 6,973,340, the entire disclosures of each of which are incorporated herein by reference.
Basket catheters typically have an elongated catheter body and a basket-shaped electrode assembly mounted at the distal end of the catheter body. The basket assembly has proximal and distal ends and comprises a plurality of spines connected at their proximal and distal ends. Each spine comprises at least one electrode. The basket assembly has an expanded arrangement wherein the spines bow radially outwardly and a collapsed arrangement wherein the spines are arranged generally along the axis of the catheter body. In some circumstances, the expanded arrangement may be achieved by proximally withdrawing a pulling member secured to the distal ends of the spines to decrease the relative longitudinal distance to the proximal ends of the spines to cause the outward bowing.
For diagnostic purposes, it is desirable that a basket assembly be capable of detecting in as few beats as possible, including a single beat, as much of the electrical function of the region in which the electrode assembly is deployed, such as the left or right atrium. To reliably achieve this goal, the basket should deploy into a specific configuration that positions the spines with a desired relative spacing to each other in order to obtain uniform coverage of the tissue in the region of interest with the electrodes carried by the spines. Similarly, when employing a basket catheter to deliver energy for a therapeutic procedure, such as tissue ablation, achieving a specific spine configuration when the basket assembly is deployed helps ensure that one or more of the electrodes carried by the spines are positioned at the intended treatment site.
Accordingly, it would be desirable to provide structural elements that control deployment of the spines to achieve a specific configuration when the basket assembly is expanded. Likewise, it would be desirable to provide a structural element at the distal end of the basket assembly that allows a pulling member to be readily secured to the distal ends of the spines. Further, it would be desirable to provide a structural element at the distal end to maintain relative radial spacing of the spines. Still further, it would be desirable to provide a structural element at the proximal end of the basket assembly to maintain relative radial spacing of the spines. The techniques of this disclosure as described in the following materials satisfy these and other needs.